With the word “behold” John is asking his readers to pay special attention to this fourth animal. We might imagine John stretching out his arm to point at what his readers must now notice. Given the contrast between the fourth animal and the other three, a reader could easily skip over this fourth creature as insignificant.
1 Then I looked, and behold, on Mount Zion stood the Lamb, and with him 144,000 who had his name and his Father’s name written on their foreheads.